/**
 * \* Created with IntelliJ IDEA.
 * \* User: Administrator
 * \* Date: 2021/12/4
 * \* Time: 17:13
 * \* To change this template use File | Settings | File Templates.
 * \* Description:
 * \
 */
class ListNode {
    public int val;
    public ListNode next;
    public ListNode prev;

    public ListNode(int val) {
        this.val = val;
    }
}
public class MyLinkedList {
    public  ListNode head;//指向双向链表的头节点
    public ListNode last;//指向双向链表的尾节点

    public int size(){
        int count=0;
        ListNode cur=this.head;
        while (cur!=null){
            count++;
            cur=cur.next;
        }
        return count;
    }
    public void display(){
        ListNode cur=this.head;
        while (cur!=null){
            System.out.print(cur.val+" ");
            cur=cur.next;
        }
        System.out.println();
    }
    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key){
        ListNode cur=this.head;
        while (cur!=null){
            if(cur.val==key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }
    //头插法
    public void addFirst(int data) {
        ListNode node=new ListNode(data);
        if(this.head==null){
            this.head=node;
            this.last=node;
        }else {
            node.next=this.head;
            head.prev=node;
            this.head=node;
        }

    }
    //尾插法
    public void addLast(int data){
        ListNode node=new ListNode(data);
        if(this.head==null){
            this.head=node;
            this.last=node;
        }else {
            this.last.next=node;
            node.prev=this.last;
            this.last=node;
        }
    }
    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index,int data){
        ListNode node = new ListNode(data);
        if(index < 0 || index > size()) {
            System.out.println("index位置不合法！");
            return;
        }
        if(index == 0) {
            addFirst(data);
            return;
        }
        if(index == size()) {
            addLast(data);
            return;
        }
        ListNode cur = searchIndex(index);
        node.next = cur.prev.next;
        cur.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;
    }

    public ListNode searchIndex (int index) {
        ListNode cur = this.head;
        while (index != 0) {
            cur = cur.next;
            index--;
        }
        return cur;
    }


    //删除第一次出现关键字为key的节点
    public void remove(int key){
        ListNode cur = this.head;
        while (cur != null) {
            if(cur.val == key) {
                if(cur == head) {
                    head = head.next;
                    if(head != null) {
                        head.prev = null;
                    }else {
                        last = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if(cur.next != null) {
                        //中间位置
                        cur.next.prev = cur.prev;
                    }else {
                        last = last.prev;
                    }
                }
                return;
            }
            cur = cur.next;
        }
    }

    //删除所有值为key的节点
    public void removeAllKey(int key){
        ListNode cur = this.head;
        while (cur != null) {
            if (cur.val == key) {
                if (cur == head) {
                    head = head.next;
                    if (head != null) {
                        head.prev = null;
                    } else {
                        last = null;
                    }
                } else {
                    cur.prev.next = cur.next;
                    if (cur.next != null) {
                        //中间位置
                        cur.next.prev = cur.prev;
                    } else {
                        last = last.prev;
                    }
                }
                //return;
            }
            cur = cur.next;
        }
    }

    //jps   jmap -histo:live XXXX > c:\\bit.txt
    public void clear() {
        while (head != null) {
            ListNode curNext = head.next;
            head.next = null;
            head.prev = null;
            head = curNext;
        }
        last = null;
    }

}
